SAN FRANCISCO— The Center for Biological Diversity filed a formal notice of intent today to sue the U.S. Fish and Wildlife Service for failing to protect the San Bernardino flying squirrel under the Endangered Species Act. This rare, truffle-eating flying squirrel is threatened by climate change, forest habitat destruction, and predation by domestic cats, and has disappeared in recent decades from one of the two mountain ranges it lives in near Los Angeles.

“These amazing flying squirrels are one of many mountaintop species being hard-hit by climate change as habitat conditions become more hostile,” said Shaye Wolf, the Center’s climate science director. “These animals have already vanished from half of their range, and they urgently need Endangered Species Act protection to survive in Southern California’s mountains.”

The Center petitioned in 2010 to have the San Bernardino flying squirrel protected under the Endangered Species Act. The animals depend on high-elevation conifer forests of Southern California, specialize in eating truffles, and can glide through the air between trees at distances up to 300 feet, using wingsuit-like flaps that extend between their wrists and ankles.

The San Bernardino flying squirrel was historically found in the San Jacinto and San Bernardino mountains, but there have been no confirmed sightings in the San Jacinto Mountains for several decades, and a recent five-year wildlife resurvey study in the region failed to find any of the squirrels.

The remaining population, in the San Bernardino Mountains, faces threats from climate change, habitat destruction and cat predation. The squirrels’ forest habitat is moving upslope as temperatures warm, and drier conditions threaten their truffle food supply, which thrives in wet, cool conditions. Misguided forest-management practices are removing the canopy cover, snags and downed logs the flying squirrels need. Urban development is encroaching on their remaining mountain habitat and increases predation by domestic cats.

In 2012 the Service determined that the San Bernardino flying squirrel “may warrant” federal protection as an endangered or threatened species. The Service is now more than two years overdue in making the required 12-month finding to decide whether protection will be granted.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 675,000 members and online activists dedicated to the protection of endangered species and wild places.